Systems and methods of utilizing surface waves for signal transmission in a downhole environment

ABSTRACT

Various embodiments include systems and methods of utilizing surface waves for signal transmission in a downhole environment. In some implementations, a system includes a first signal transceiver assembly located in a surface environment of a well and a second signal transceiver assembly located in a downhole environment of the well. The first signal transceiver assembly is configured to transmit a set of communication signals to the second signal transceiver assembly via surface waves that propagate from the surface environment to the downhole environment along an interface between one or more dielectrics and a conductive layer. The second signal transceiver assembly is configured to receive the set of communication signals from the first signal transceiver assembly via the surface waves that propagate along the interface.

BACKGROUND

A well (e.g., an oil or gas well) for extracting hydrocarbons from a subterranean formation may include various tools and/or sensors in a downhole environment. In some cases, a wired connection may be employed for communications and/or for supplying power to the downhole environment. In other cases, wireless communication systems may be employed. However, there are numerous shortcomings and limitations associated with existing communication and power delivery systems. Accordingly, there is a need for improved systems and methods for signal transmission between a surface environment of a well and a downhole environment.

SUMMARY OF EMBODIMENTS

The systems and methods described herein may be employed in various combinations and in embodiments to utilize surface waves for signal transmission in a downhole environment. In some cases, the systems and methods described herein may utilize surface waves for communication in a downhole environment. In some cases, the systems and methods described herein may utilize surface waves for power transmission in a downhole environment. In some cases, the systems and methods described herein may utilize surface waves for communication/power transmission in a downhole environment during a drilling and completions stage of a well's lifecycle. In some cases, the systems and methods described herein may utilize surface waves for communication/power transmission in a downhole environment during a production stage of a well's lifecycle. In some cases, the systems and methods described herein may utilize surface waves for communication/power transmission in a downhole environment during an abandonment stage of a well's lifecycle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a system that utilizes surface waves for signal transmission in a downhole environment, in accordance with some embodiments.

FIG. 2A is a diagram illustrating a first signal transceiver assembly being positioned at an example location in a surface environment to utilize surface waves for signal transmission during a drilling and completions stage, in accordance with some embodiments.

FIG. 2B is a diagram illustrating a second signal transceiver assembly being positioned at an example location in a downhole environment to utilize surface waves for signal transmission during the drilling and completions stage, in accordance with some embodiments.

FIG. 3A is a diagram illustrating a first signal transceiver assembly being positioned at an example location in a surface environment to utilize surface waves for signal transmission during a production stage, in accordance with some embodiments.

FIG. 3B is a diagram illustrating a second signal transceiver assembly being positioned at an example location in a downhole environment to utilize surface waves for signal transmission during the production stage, in accordance with some embodiments.

FIG. 4A is a diagram illustrating a first signal transceiver assembly being positioned at an example location in a surface environment to utilize surface waves for signal transmission during an abandonment stage, in accordance with some embodiments.

FIG. 4B is a diagram illustrating a second signal transceiver assembly being positioned at an example location in a downhole environment to utilize surface waves for signal transmission during the abandonment stage, in accordance with some embodiments.

FIG. 5 is a diagram illustrating path loss data associated with air being utilized as a dielectric medium at a dielectric/conductor interface for surface wave excitation and propagation, in accordance with some embodiments.

FIG. 6 is a diagram illustrating path loss data associated with water being utilized as a dielectric medium at a dielectric/conductor interface for surface wave excitation and propagation, in accordance with some embodiments.

FIG. 7 is a diagram illustrating a top view of an example transmitter design for a signal transceiver assembly, in accordance with some embodiments.

FIG. 8 is a diagram illustrating a perspective view and a top view of an example antenna design for a downhole signal transceiver assembly, in accordance with some embodiments.

FIG. 9 is a diagram illustrating a top view and a perspective view of an example antenna design for a surface signal transceiver assembly, in accordance with some embodiments.

FIG. 10 is a diagram illustrating a top view of an example receiver design for a signal transceiver assembly, in accordance with some embodiments.

FIG. 11 is a flowchart that illustrates an example process of utilizing surface waves for communication in a downhole environment during a drilling and completion stage, in accordance with some embodiments.

FIG. 12 is a flowchart that illustrates an example process of utilizing surface waves for power transmission in a downhole environment during a drilling and completion stage, in accordance with some embodiments.

FIG. 13 is a flowchart that illustrates an example process of utilizing surface waves for communication in a downhole environment during a production stage, in accordance with some embodiments.

FIG. 14 is a flowchart that illustrates an example process of utilizing surface waves for power transmission in a downhole environment during a production stage, in accordance with some embodiments.

FIG. 15 is a flowchart that illustrates an example process of utilizing surface waves for communication in a downhole environment during an abandonment stage, in accordance with some embodiments.

FIG. 16 is a flowchart that illustrates an example process of utilizing surface waves for power transmission in a downhole environment during an abandonment stage, in accordance with some embodiments.

FIG. 17 is a block diagram illustrating an example computer system that may be used to implement one or more portions of a system that utilizes surface waves for signal transmission in a downhole environment, according to some embodiments.

While embodiments are described herein by way of example for several embodiments and illustrative drawings, those skilled in the art will recognize that embodiments are not limited to the embodiments or drawings described. It should be understood that the drawings and detailed description thereto are not intended to limit embodiments to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope as defined by the appended claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to.

DETAILED DESCRIPTION OF EMBODIMENTS

The systems and methods of the present disclosure enable bi-directional high-speed communication and/or power transmission in a typical downhole environment, via the transmission of surface waves. The surface waves of the present disclosure may be considered analogous to Sommerfield-Zenneck surface waves, which may propagate along an interface between the atmosphere and ground or along an interface between the atmosphere and water (e.g, lakes or oceans). Such waves are created when electromagnetic radiation interacts with an interface between two materials, one being a conductor and one being an insulator (i.e., a dielectric). When this interaction occurs, a surface wave is excited at the interface between the conductor and the dielectric. This surface wave is guided by the interface and experiences relatively small path loss when compared to most other electromagnetic transmission mechanisms (also known as “electromagnetic modes”) in a typical downhole environment. The low path loss characteristics are advantageous for electromagnetic communication and/or power transfer in a downhole environment. As described further herein, the systems and methods of the present disclosure utilize surface waves that are created either downhole or at or near the surface and transmitted along the well path of a typical downhole environment and that are received with high fidelity at the other end or any point along the way. As used herein, the term “surface environment” refers to a location at or near ground level (e.g., slightly above ground level, at ground level, or slightly below ground level). The systems and methods of the present disclosure may be utilized in various stages of a well's lifecycle, including drilling and completions, production, and abandonment.

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that some embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

Referring to FIG. 1 , a diagram 100 illustrates an example system that utilizes surface waves for signal transmission in a downhole environment, according to some embodiments. In the example depicted in FIG. 1 , a first signal transceiver assembly 102 is located in a surface environment and a second signal transceiver assembly 104 is located in a downhole environment. FIG. 1 illustrates a particular embodiment in which the signal transceiver assemblies 102, 104 are utilized during a drilling and completions stage of a well's lifecycle. As further described herein, in alternative embodiments, the signal transceiver assemblies 102, 104 may be utilized during a production stage of the well's lifecycle (see e.g., FIGS. 3A and 3B) or during an abandonment stage of the well's lifecycle (see e.g., FIGS. 4A and 4B).

FIG. 1 illustrates that, during the drilling and completions stage of a well's lifecycle, a rig 110 may be located at the surface (exposed to air 112) to enable drilling into a formation 114 for hydrocarbon extraction (or potentially for geothermal purposes and/or other wellbore construction such as injector wells, salt water disposal, utilities, etc.). In FIG. 1 , a first callout (identified by dashed lines) illustrates a more detailed view of a first portion of a downhole environment at a relatively shallow depth beneath the rig 110, and a second callout (identified by dashed lines) illustrates a more detailed view of a second portion of a downhole environment at a relatively deep location in the formation 114.

Referring to the first portion of the downhole environment, FIG. 1 illustrates that a well is typically drilled in sequences of telescoping hole size. The first hole is drilled with a large diameter to a certain depth, using fluids (i.e., liquids or gases) under high flow rates to remove the cuttings and prevent the wellbore from caving in. Subsequently, casing 120 is inserted into the drilled hole and fixed in place using cement 122 between the drilled hole and the outside diameter of the casing 120. This process is typically repeated several times until the well has been drilled to the desired depth (also referred to as a true vertical depth) and length (also referred to as a measured depth). FIG. 1 illustrates that a drill pipe 124 and drilling fluid 126 are located within an area adjacent to the casing 120 having the narrowest diameter in the telescoping sequence (i.e., an innermost portion of the casing 120) in order to continue drilling operations. From an electrical perspective, the aforementioned drilling and completions environment is suitable to function as a transmission line for surface waves in a downhole environment (analogous to Sommerfield-Zenneck surface waves in an atmospheric environment). The environment contains multiple successive layers of dielectrics and conductors that are fortuitously sequenced. For example, the air 112 is a dielectric, the rig 110 is a conductor, the formation 114 may be a dielectric or a conductor, each layer of cement 122 is a dielectric, each layer of casing 120 is a conductor, the drilling fluid 126 may be a dielectric (or a conductor in some cases, such as salt water in an offshore environment), and the drill pipe 124 is a conductor.

In some embodiments, as further described herein, the first signal transceiver assembly 102 may be utilized to transmit and/or receive communication signals (e.g., “small” signals having a relatively small signal strength compared to power signals) to/from the downhole environment via surface waves that propagate along a dielectric/conductor interface. In some embodiments, as further described herein, the first signal transceiver assembly 102 may be utilized to wirelessly transmit power signals (e.g., “large” signals having a relatively large signal strength compared to the aforementioned communication signals) to the downhole environment via surface waves that propagate along one or more dielectric/conductor interfaces, and the power may be utilized by the second signal transceiver assembly 104 (e.g., to provide power to one or more downhole tools, such as a measurement-while-drilling (MWD) tool, among other possibilities). Further details regarding a particular embodiment of a transmitter design which may be utilized to transmit communication/power signals to the downhole environment are further described herein with respect to FIG. 7 . Additionally, further details regarding a particular embodiment of a receiver design which may be utilized to receive communication signals from the downhole environment are further described herein with respect to FIG. 10 .

Referring to the second portion of the downhole environment deeper under the surface within the formation 114, FIG. 1 illustrates that a distal end of the drill pipe 124 may include a bottom hole assembly 130 adjacent to a drill bit 132. In various cases, the bottom hole assembly 130 may contain one or more measurement-while-drilling (MWD) components (not shown) that be configured to collect drilling data or perform downhole actions such as steering the drill bit 132 within the formation 114, among other possibilities.

As previously described, a surface wave is excited when an electromagnetic field (of an appropriate frequency) interacts with the interface (or boundary) between a conductor and a dielectric. As described above, multiple conductor/dielectric interfaces exist in the drilling and completions environment. Each of these interfaces may support the excitation and the transmission of the surface wave. Accordingly, the present disclosure contemplates utilizing any of the conductor/dielectric interfaces in the downhole environment as viable transmission lines for surface waves. In a particular embodiment, the interface between the drill pipe 124 (a conductor) and the drilling fluid 126 (a dielectric) may be utilized as a transmission line for a surface wave during the drilling and completions stage.

In a particular embodiment, as illustrated and further described herein with respect to FIG. 2A, the first signal transceiver assembly 102 may have a form factor that allows for positioning around an outside diameter (OD) of the drill pipe 124. In some cases, the first signal transceiver assembly 102 may be exposed to the air 112 in the surface environment of the rig 110, such that the air 112 acts as the dielectric and the drill pipe 124 (e.g., a steel pipe) acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. In other cases, the first signal transceiver assembly 102 may be immersed in the drilling fluid 126 under the rig 110, such that the drilling fluid 126 (e.g., drilling “mud” or fresh water) acts as the dielectric and the drill pipe 124 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. Alternatively, the first signal transceiver assembly 102 may have a form factor that allows for positioning inside the drill pipe 124 such that it is immersed in the drilling fluid 126. Other example alternatives include positioning the first signal transceiver assembly 102 inside a blowout preventer (not shown) on the rig 110 or inside a rotating housing (not shown) on the rig 110, among other possibilities. It should be noted that a surface wave may be excited at any of the interfaces that are within one wavelength of a near field signal (e.g., a 10 MHz signal). Additionally, it should be noted that a surface wave may be excited at any of the interfaces that are within an evanescent field of a far field signal (which is also referred to as the “Otto Effect”).

In a particular embodiment, as illustrated and further described herein with respect to FIG. 2B, the second signal transceiver assembly 104 may have a form factor that allows for positioning inside an inside diameter (ID) of the drill pipe 124 in the downhole environment. In some cases, the second signal transceiver assembly 104 may be immersed in the drilling fluid 126 within the drill pipe 124, such that the drilling fluid 126 (e.g., drilling “mud” or fresh water) acts as the dielectric and the drill pipe 124 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. Alternatively, the second signal transceiver assembly 104 may have a form factor that allows for positioning outside the OD of the drill pipe 124 in the downhole environment such that it is immersed in the drilling fluid 126.

In some embodiments, as further described herein, the second signal transceiver assembly 104 may be utilized to transmit and/or receive communication signals to/from the surface environment via surface waves that propagate along a dielectric/conductor interface. In some embodiments, as further described herein, the second signal transceiver assembly 104 may receive power that is transmitted to the downhole environment via surface waves that propagate along a dielectric/conductor interface, and the second signal transceiver assembly 104 may utilize the power (e.g., to provide power to one or more downhole tools, such as a MWD tool, among other possibilities). Further details regarding a particular embodiment of a transmitter design which may be utilized to transmit communication signals to the surface environment are further described herein with respect to FIG. 7 . Additionally, further details regarding a particular embodiment of a receiver design which may be utilized to receive communication/power signals from the surface environment are further described herein with respect to FIG. 10 .

Thus, FIG. 1 illustrates an example of a system that utilizes surface waves for signal transmission in a downhole environment. FIG. 1 depicts a particular embodiment in which in which the signal transceiver assemblies 102, 104 are utilized during a drilling and completions stage of a well's lifecycle. FIGS. 2A and 2B depict particular examples of example locations for positioning of the signal transceiver assemblies 102, 104 in the surface and downhole environments, respectively, in order to utilize surface waves as signals during the drilling and completions stage.

Referring to FIG. 2A, a diagram 200 illustrates a particular embodiment in which the first signal transceiver assembly 102 of FIG. 1 is positioned at an example location in the surface environment to utilize surface waves for signal transmission during the drilling and completions stage. In the particular embodiment depicted in FIG. 2A, the first signal transceiver assembly 102 has a form factor that allows for positioning around an OD of the drill pipe 124 (e.g., a steel pipe, an aluminum pipe, or a non-magnetic material). For illustrative purposes only, FIG. 2A depicts the first signal transceiver assembly 102 as exposed to the air 112, such that the air 112 acts as the dielectric and the drill pipe 124 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. As illustrated and described further herein with respect to FIGS. 5 and 6 , the drilling fluid 126 may offer superior performance characteristics as a dielectric compared to the air 112. As such, in alternative embodiments, the first signal transceiver assembly 102 may be positioned such that it is immersed in the drilling fluid 126 rather than exposed to the air 112.

FIG. 2A illustrates that the first signal transceiver assembly 102 may include a transmitter 210, a transmit antenna 212, a receiver 214, a receive antenna 216, and one or more other components 218 (e.g., processing logic, etc.). In a particular embodiment, the transmitter 210 of the first signal transceiver assembly 102 may have a design corresponding to the transmitter design that is illustrated and further described herein with respect to FIG. 7 . In a particular embodiment, the receiver 214 of the first signal transceiver assembly 102 may have a design corresponding to the receiver design that is illustrated and further described herein with respect to FIG. 10 . In a particular embodiment, the first signal transceiver assembly 102 may have an antenna design corresponding to the antenna design that is illustrated and further described herein with respect to FIG. 9 , where the transmit antenna 212 corresponds to the transmit antenna 902 and the receive antenna 216 corresponds to the receive antenna 904.

FIG. 2A depicts a particular embodiment in which the first signal transceiver assembly 102 is positioned such that surface wave excitation and propagation may occur along a dielectric/conductor interface between the air 112 and the drill pipe 124. However, from an electrical perspective, the drilling and completions environment contains multiple successive layers of dielectrics and conductors that are fortuitously sequenced. As such, other dielectric/conductor interfaces may also be suitable to function as a transmission line for surface waves. In FIG. 2A, an example of a telescoping sequence of layers includes: a first cement layer 122(a), representing an outermost layer of the cement 122; a first casing layer 120(a), representing an outermost layer of the casing 120; a second cement layer 122(b); a second casing layer 120(b); a third cement layer 122(c); a third casing layer 120(c); a fourth cement layer 122(d); a fourth casing layer 120(d); a fifth cement layer 122(e), representing an innermost layer of the cement 122; and a fifth casing layer 120(e), representing an innermost layer of the casing 120. Each of the interfaces between these cement/casing layers represent dielectric/conductor interfaces.

An illustrative, non-limiting example is as follows: the first casing layer 120(a) may be a conductive metal pipe having a nominal diameter of twenty-six (26) inches; the second casing layer 120(b) may be a conductive metal pipe having a nominal diameter of seventeen-and-one-half (17.5) inches; the third casing layer 120(c) may be a conductive metal pipe having a nominal diameter of twelve-and-one-half (12.5) inches; the fourth casing layer 120(d) may be a conductive metal pipe having a nominal diameter of eight-and-one-half (8.5) inches; and the fifth casing layer 120(e) may be a conductive metal pipe having a nominal diameter of six (6) inches. FIG. 2A illustrates that the fifth casing layer 120(e), representing the innermost layer of the casing 120 of FIG. 1 , interfaces with the drilling fluid 126 (a dielectric) in which the drill pipe 124 (a conductor) is immersed. As such, the interface between the fifth casing layer 120(e) and the drilling fluid 126 represents another conductor/dielectric interface that may be utilized for surface wave excitation and propagation. Further, as previously noted, the interface between the drill pipe 124 and the drilling fluid 126 also represents a conductor/dielectric interface that may be utilized for surface wave excitation and propagation.

Thus, FIG. 2A illustrates one example of the first signal transceiver assembly 102 of FIG. 1 being positioned at an example location in the surface environment to utilize surface waves for signal transmission during the drilling and completions stage. FIG. 2A further illustrates details of the telescoping sequence of layers beneath the rig 110 of FIG. 1 , with multiple possible conductor/dielectric interfaces that may be utilized to propagate surface waves for signal transmission during the drilling and completions stage.

Referring to FIG. 2B, a diagram 230 illustrates a particular embodiment in which the second signal transceiver assembly 104 of FIG. 1 is positioned at an example location in the downhole environment to utilize surface waves for signal transmission during the drilling and completions stage. In the particular embodiment depicted in FIG. 2B, the second signal transceiver assembly 104 has a form factor that allows for positioning inside an inner diameter (ID) of the drill pipe 124 (e.g., a steel pipe). FIG. 2B depicts the second signal transceiver assembly 104 as immersed within the drilling fluid 126 inside the ID of the drill pipe 124, such that the drilling fluid 126 acts as the dielectric and the drill pipe 124 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. In alternative embodiments, the second signal transceiver assembly 104 may have a form factor that allows for positioning outside an OD of the drill pipe 124. In this case, the second signal transceiver assembly 104 may be immersed in the drilling fluid 126 outside the OD of the drill pipe 124, such that the drilling fluid 126 acts as the dielectric and the drill pipe 124 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface.

FIG. 2B illustrates that the second signal transceiver assembly 104 may include a transmitter 240, a transmit antenna 242, a receiver 244, a receive antenna 246, and one or more other components 248 (e.g., processing logic, etc.). In a particular embodiment, the transmitter 240 of the second signal transceiver assembly 104 may have a design corresponding to the transmitter design that is illustrated and further described herein with respect to FIG. 7 . In a particular embodiment, the receiver 244 of the second signal transceiver assembly 104 may have a design corresponding to the receiver design that is illustrated and further described herein with respect to FIG. 10 . In a particular embodiment, the second signal transceiver assembly 104 may have an antenna design corresponding to the antenna design that is illustrated and further described herein with respect to FIG. 8 , where the transmit antenna 242 corresponds to the transmit antenna 802 and the receive antenna 246 corresponds to the receive antenna 804.

Thus, FIG. 2B illustrates one example of the second signal transceiver assembly 104 of FIG. 1 being positioned at an example location in the downhole environment to utilize surface waves for signal transmission during the drilling and completions stage. FIG. 2B further illustrates details of the downhole environment, with multiple possible conductor/dielectric interfaces that may be utilized to propagate surface waves for signal transmission during the drilling and completions stage.

As illustrated and further described herein with respect to FIGS. 3A and 3B, wireless communication and/or power transmission have applicability in the oil well production environment as well. The production environment is very similar to the aforementioned drilling and completions environment, with some changes. One change is that, in a production environment, the drill pipe 124 is replaced with a production pipe 324, which is also a conductor. Another change is that, in the production environment, the drilling fluid 126 is replaced with air or water (fresh) as a production fluid 326, which is also a dielectric. In such a production environment, the interface between the production pipe 324 (conductor) and the production fluid 326 (dielectric) may support the transmission of surface waves in a manner similar to the drill pipe/drilling fluid interface of the drilling and completions environment.

Referring to FIG. 3A, a diagram 300 illustrates a particular embodiment in which the first signal transceiver assembly 102 of FIG. 1 is positioned at an example location in the surface environment to utilize surface waves for signal transmission during a production stage of a well's lifecycle. FIG. 3A illustrates that, in the production stage, the drill pipe 124 is replaced with the production pipe 324 and the drilling fluid 126 is replaced with the production fluid 326 (e.g., air or water). In the particular embodiment depicted in FIG. 3A, the first signal transceiver assembly 102 has a form factor that allows for positioning around an OD of the production pipe 324 (e.g., a steel pipe). For illustrative purposes only, FIG. 3A depicts the first signal transceiver assembly 102 as exposed to the air 112, such that the air 112 acts as the dielectric and the production pipe 324 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. As illustrated and described further herein with respect to FIGS. 5 and 6 , in cases where the production fluid 326 is fresh water, the water may offer superior performance characteristics as a dielectric compared to the air 112. As such, in alternative embodiments, the first signal transceiver assembly 102 may be positioned such that it is immersed in the production fluid 326 rather than exposed to the air 112.

FIG. 3A depicts a particular embodiment in which the first signal transceiver assembly 102 is positioned such that surface wave excitation and propagation may occur along a dielectric/conductor interface between the air 112 and the production pipe 324. However, from an electrical perspective, as was the case in the drilling and completions environment, FIG. 3A illustrates that the production environment also contains multiple successive layers of dielectrics and conductors that are fortuitously sequenced. As such, other dielectric/conductor interfaces may also be suitable to function as a transmission line for surface waves, in a manner similar to that described previously herein with respect to the drilling and completions environment depicted in FIG. 2A. For example, in the production environment, each of the interfaces between the cement layers (e.g., the first cement layer 122(a) through the fifth cement layer 122(e)) and the corresponding casing layers (e.g., the first casing layer 120(a) through the fifth casing layer 120(e)) represent dielectric/conductor interfaces. Further, FIG. 3A illustrates that the fifth casing layer 120(e), representing the innermost layer of the casing 120 of FIG. 1 , interfaces with the production fluid 326 (a dielectric) in which the production pipe 324 (a conductor) is immersed. As such, the interface between the fifth casing layer 120(e) and the production fluid 326 represents another conductor/dielectric interface that may be utilized for surface wave excitation and propagation. Further, as previously noted, the interface between the production pipe 324 and the production fluid 326 also represents a conductor/dielectric interface that may be utilized for surface wave excitation and propagation.

Thus, FIG. 3A illustrates one example of the first signal transceiver assembly 102 of FIG. 1 being positioned at an example location in the surface environment to utilize surface waves for signal transmission during the production stage. FIG. 3A further illustrates details of the telescoping sequence of layers beneath the rig 110 of FIG. 1 , with multiple possible conductor/dielectric interfaces that may be utilized to propagate surface waves for signal transmission during the production stage.

Referring to FIG. 3B, a diagram 330 illustrates a particular embodiment in which the second signal transceiver assembly 104 of FIG. 1 is positioned at an example location in the downhole environment to utilize surface waves for signal transmission during the production stage.

In the particular embodiment depicted in FIG. 3B, the second signal transceiver assembly 104 has a form factor that allows for positioning inside an inner diameter (ID) of the production pipe 324 (e.g., a steel pipe). FIG. 3B depicts the second signal transceiver assembly 104 as immersed within the production fluid 326 inside the ID of the production pipe 324, such that the production fluid 326 acts as the dielectric and the production pipe 324 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. In alternative embodiments, the second signal transceiver assembly 104 may have a form factor that allows for positioning outside an OD of the production pipe 324. In this case, the second signal transceiver assembly 104 may be immersed in the production fluid 326 outside the OD of the production pipe 324, such that the production fluid 326 acts as the dielectric and the production pipe 324 acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface.

Thus, FIG. 3B illustrates one example of the second signal transceiver assembly 104 of FIG. 1 being positioned at an example location in the downhole environment to utilize surface waves for signal transmission during the production stage. FIG. 3B further illustrates details of the downhole environment, with multiple possible conductor/dielectric interfaces that may be utilized to propagate surface waves for signal transmission during the production stage.

As illustrated and described further herein with respect to FIGS. 4A and 4B, wireless communication and/or power transmission have applicability in the oil well abandonment environment as well. The abandonment environment is very similar to the aforementioned drilling and completions environment, with the following change. FIG. 4A illustrates that, during abandonment, a well plug 410 is added upon removal of the rig 110. Additionally, FIGS. 4A and 4B illustrate that, during abandonment, the drill pipe 124 and the drilling fluid 126 are replaced with barrier material 422 (e.g., cement). In contrast to the drilling and completions environment and the production environment, the innermost conductor/dielectric interface is typically not present in the abandonment environment (although in some cases an operator may elect to leave the production pipe 324 or to place some other conductive material in the hole in order for improved communication potential). However, the various layers of casing (conductor) and cement (dielectric) are still present in the abandonment environment. Accordingly, in the abandonment environment, these layers may support the transmission of surface waves in a manner similar to the interfaces that are utilized in the drilling and completions environment and the production environment.

Referring to FIG. 4A, a diagram 400 illustrates a particular embodiment in which the first signal transceiver assembly 102 of FIG. 1 is positioned at an example location to utilize surface waves for signal transmission during an abandonment stage of a well's lifecycle.

In the particular embodiment depicted in FIG. 4A, the first signal transceiver assembly 102 has a form factor that allows for positioning within the innermost casing layer 120(e), either before or during the addition of the cement 422 into the area previously utilized for the production pipe 324 and the production fluid 326. For illustrative purposes only, FIG. 4A depicts the first signal transceiver assembly 102 as immersed in the barrier material 422, such that the barrier material 422 acts as the dielectric and the innermost casing layer 120(e) acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface. In alternative embodiments, the first signal transceiver assembly 102 may be positioned at one of the other remaining dielectric/conductor interfaces previously described herein.

Thus, FIG. 4A illustrates one example of the first signal transceiver assembly 102 of FIG. 1 being positioned at an example location to utilize surface waves for signal transmission during the abandonment stage. FIG. 4A further illustrates details of the telescoping sequence of layers beneath the rig 110 of FIG. 1 , with multiple possible conductor/dielectric interfaces that may be utilized to propagate surface waves for signal transmission during the abandonment stage.

Referring to FIG. 4B, a diagram 430 illustrates a particular embodiment in which the second signal transceiver assembly 104 of FIG. 1 is positioned at an example location in the downhole environment to utilize surface waves for signal transmission during the abandonment stage.

In the particular embodiment depicted in FIG. 4B, the second signal transceiver assembly 104 has a form factor that allows for positioning inside an inner diameter (ID) of the fifth casing layer 120(e) (e.g., the innermost casing layer). FIG. 4B depicts the second signal transceiver assembly 104 as immersed within the barrier material 422 that is added at abandonment to replace the production pipe 324 and the production fluid 326, such that the barrier material 422 acts as the dielectric and the fifth casing layer 120(e) acts as the conductor for surface wave excitation and propagation along this dielectric/conductor interface.

Thus, FIG. 4B illustrates one example of the second signal transceiver assembly 104 of FIG. 1 being positioned at an example location in the downhole environment to utilize surface waves for signal transmission during the abandonment stage. FIG. 4B further illustrates details of the downhole environment, with multiple possible conductor/dielectric interfaces that may be utilized to propagate surface waves for signal transmission during the abandonment stage.

In the present disclosure, the wave that is generated is a guided surface wave not a waveguide mode, as the present disclosure contemplates operation below the waveguide cutoff frequency for the downhole environment. With regard to behavior of the channel, research information is lacking with regard to the behavior of a surface wave in anything approaching the aforementioned downhole environments. However, physical explanations exist for the propagation of surface waves in other environments, such as the earth/air interface and the sea/air interface for the Sommerfield-Zenneck surface wave. Accordingly, a combination of analytical channel modeling and numerical channel modeling were employed to predict channel performance in the aforementioned downhole environments. The inventor performed various small-scale and large-scale experiments to obtain empirical research data that was utilized to refine these models to a significant degree.

The inventor has discovered that, in the downhole environment, any of the aforementioned interfaces that are within one (1) wavelength radius from the transmitter will develop a surface wave. The inventor has further discovered that the closer the interfaces are to the transmitter, the more powerful the surface wave becomes. As with all electromagnetic signals, there are two components to the surface wave: a magnetic component and an electrical component.

Based on a ten (10) megahertz (MHz) simulation of a magnetic field, the inventor has discovered that the electrical and magnetic components of the evanescent field display characteristics of a longitudinal wave, as described by Heavyside and Maxwell. The longitudinal wave, also known as a “slow wave” travels significantly slower than the speed of light, propagating at approximately ten (10) percent of the speed of light. The empirical reception of this signal via an inductive antenna remote to the conductor proves that this field exists.

Based on a ten (10) MHz simulation of an electric field, the inventor has discovered that the surface wave's electric field is significantly different from its magnetic field. The electric field of the surface wave appears as eddy currents on the surfaces of the conductors in the downhole environment. This has been empirically proven via the reception of signals through a galvanic connection to the conductor.

Referring to FIG. 5 , a diagram 500 illustrates path loss data associated with air being utilized as a dielectric medium at a dielectric/conductor interface for surface wave excitation and propagation, in accordance with some embodiments. Based on all analytical, numerical and empirical analysis, FIG. 5 represents an estimation of the surface wave's path loss with air as the dielectric and with carbon steel as the conductor.

One conclusion that can be drawn from the data depicted in FIG. 5 is that a signal will be receivable without noise filters up to 9,387 feet downhole. Another conclusion that can be drawn from the data depicted in FIG. 5 is that one repeater may be added in order to communicate to a downhole depth of about twenty thousand feet. Yet another conclusion that can be drawn from the data depicted in FIG. 5 is that, alternatively, receiver filters that reduce background noise to less than −31 dBW may be added in order to communicate to a downhole depth of about twenty thousand feet. Yet another conclusion that can be drawn from the data depicted in FIG. 5 is that, alternatively, a transmitter gain increase of 9.6 dBW may allow filter-less, repeater-less reception of signal at a downhole depth of about twenty thousand feet.

Referring to FIG. 6 , a diagram 600 illustrates path loss data associated with water being utilized as a dielectric medium at a dielectric/conductor interface for surface wave excitation and propagation, in accordance with some embodiments.

FIG. 6 illustrates that, with water as the dielectric, the signal is approximately four (4) times stronger than the signal with air as the dielectric. This is due to the dielectric constant of water being significantly greater than the dielectric constant of air. The dielectric constant of air is roughly equivalent to concrete and to a vacuum. It is also worth noting that, in some embodiments, dielectric and conductive elements may be added to the drilling fluid and concrete to create an improved environment for transmission of a surface wave in a downhole environment.

One conclusion that can be drawn from the data depicted in FIG. 6 is that a signal may be receivable downhole without noise filters a downhole depth of about twenty thousand feet (receivable up to 29,080 feet). Another conclusion that can be drawn from the data depicted in FIG. 6 is that no repeaters may be required in order to communicate to a downhole depth of about twenty thousand feet. Yet another conclusion that can be drawn from the data depicted in FIG. 6 is that receiver filters may not be necessary to enable communication between the surface and a downhole depth of about twenty thousand feet. Yet another conclusion that can be drawn from the data depicted in FIG. 6 is that a transmitter gain may be decreased by about −3.5 dBW and still yield filter-less, repeater-less reception of signal at a downhole depth of about twenty thousand feet.

With regard to frequency response, analytical analysis of the surface wave by the inventor revealed that frequency has a significant effect on the attenuation of the wave. It has been shown that surface waves propagate with the least attenuation when modulated in a frequency band of twenty (2) kilohertz (KHz) to one (1) MHz. The wave's attenuation increases logarithmically with frequencies greater than one (1) MHz. However, even though attenuated, numerical and analytical analysis by the inventor revealed that a signal of 20 MHz has an acceptable amount of attenuation for signal reception and demodulation. Based on an analysis of surface waves of one hundred (100) MHz or greater, the inventor determined that the surface wave exhibited a very limited transmission distance and would not be useful in a downhole environment. Frequencies of less than twenty (20) KHz were not of interest to the inventor, and were not studied, as such frequencies do not support high data rates and approach the realm of conventional oilfield electromagnetic telemetry low frequency and extremely low frequency systems. Thus, the inventor has determined that surface waves in range between twenty (20) KHz and twenty (20) MHz may be satisfactory to function properly in a downhole environment. Waveforms were also studied, and it was determined that a square waveform may produce the highest gain (i.e., strongest signal). Various waveform shapes that may be satisfactory include the square waveform, sine waveform, and ramp waveform.

Referring to FIG. 7 , a diagram 700 illustrates a top view of an example design for a transmitter, in accordance with some embodiments. In some embodiments, the design depicted in FIG. 7 may be utilized for the transmitter 210 of the first signal transceiver assembly 102 depicted in FIGS. 2A, 3A, and 4A. In some embodiments, the design depicted in FIG. 7 may be utilized for the transmitter 240 of the second signal transceiver assembly 104 depicted in FIGS. 2B, 3B, and 4B.

The transmitter is the first step in the signal's transmission. It is responsible for creating the frequency, wave form, modulation, and high voltage/current output for the antenna. In a particular embodiment, the transmitter of the present disclosure includes at least three components including: a 555 timer 702; a gate driver 704; and a Darlington Amplifier Array 706.

With respect to the 555 timer 702, the transmission of the signal begins with the creation of a wave having a particular waveform (e.g., a square wave) at a particular frequency (e.g., 10 MHz). In a particular embodiment, the wave has a square waveform that is modulated by turning it off and on, creating “bursts” of medium frequency electromagnetic signals that are modulated as ones and zeroes. This modulation method is typically referred to as “on-off keying (OOK)” or “analog shift keying (ASK).” It will be appreciated that additional modulations are possible with this channel, such as: amplitude modulation (AM); frequency modulation (FM); and other forms of quadrature amplitude modulation (QUAM-XX). Such alternative modulations may enable higher data rates but are significantly more complicated to implement compared to OOK modulation.

When used for transmitting power, the 555 timer 702 may have a signal that is a constant, unmodulated signal operating on a different frequency. An unmodulated signal operating on a different frequency may be utilized to transmit uninterrupted power and to reduce interference with communication channels. In some cases, as an alternative to OOK modulation, frequency modulation may be utilized in order to allow the transmission of power and data over the same frequency.

With respect to the gate driver 704, the gate driver 704 amplifies the signal from the 555 timer 702 to voltage levels that are sufficient to drive the gate of the first P-channel MOSFET in the Darlington Transistor Array 706.

With respect to the Darlington Transistor Array 706, two cascaded P-channel MOSFET transistors may be configured to receive the signal from the gate driver 704 and to amplify the voltage and current. P-channel MOSFETs may be advantageous compared to N-channel MOSFETs, as N-channel MOSFETs may cause the transmitting antenna voltage to become trapped in a high state, which may affect its performance when modulated as medium frequencies. As P-channel MOSFETs are driven from the ground, when turned off, the voltage/current may rapidly drain to a ground level.

Referring to FIG. 8 , a diagram 800 illustrates a perspective view and a top view of an example antenna design for a downhole signal transceiver assembly, in accordance with some embodiments. FIG. 8 illustrates that the antenna design includes a transmit antenna 802 and a receive antenna 804. In some embodiments, the antenna design depicted in FIG. 8 may be utilized in the second signal transceiver assembly 104 depicted in FIGS. 2B, 3B, and 4B. For example, the transmit antenna 802 of FIG. 8 may correspond to the transmit antenna 242 depicted in FIGS. 2B, 3B, and 4B, and the receive antenna 804 of FIG. 8 may correspond to the receive antenna 246 depicted in FIGS. 2B, 3B, and 4B.

In a particular embodiment, the transmitting antenna design has a coil/solenoid shape. The inventor has discovered that the electromagnetic near field created by a coil/solenoid interacts with the interfaces in the downhole environment, exciting surface waves. Based on this discovery, the inventor recognized that this wave could be excited by other antenna types, such as dipole and monopole antennas. However, in order to function properly, these alternative antenna types would have to be unacceptably long, having a length of at least one-quarter inch of the transmitted wavelength. For the frequency band contemplated by the present disclosure, this would correspond to an antenna length between 25 feet and 2.3 miles, which is impractical for implementation in a downhole environment. Accordingly, a tightly-wound helical solenoid antenna is advantageous, as wrapping multiple miles (e.g., 2.3 miles) of 0.020-inch magnet wire around a small diameter (e.g., 1.5-inch) antenna core occupies significantly less distance than a straight wire. Accordingly, in a particular embodiment, the design of the transmitting antenna may be a tightly-wound helical solenoid using magnet wire 810 (having a wire diameter that is larger in radius than the skin depth, such as 22 AWG wire as one example).

There are other advantageous properties associated with a solenoid-type antenna design. Research studies indicate that solenoid antennas appear to have a significantly larger resonant frequency band. This characteristic makes such an antenna resonant with a wide range of transmitted frequencies. Additionally, the harmonic frequencies do not occur in normal intervals from the resonant frequency. While this is neither advantageous nor disadvantageous, it is an important consideration when designing and implementing antennas. Transmitting at the resonant frequency of the transmitting antenna, or a harmonic thereof, may produce the maximum transmitted signal gain. Accordingly, in a particular embodiment, the transmit antenna 802 may be designed to resonate at or near the transmitted frequency. The gain of the transmit antenna 802 may be further enhanced by using a conductive body 812, such as aluminum or ferrite, as the core. Accordingly, in some embodiments, the transmitting antenna may have a core that is made of a conductive material.

In some embodiments, the transmitting antenna may be placed concentrically or eccentrically along a long axis of the downhole environment. The transmitting antenna may be located on the inside or around the outside of any conducting body in the downhole environment. With respect to transmission from downhole to surface, the transmitting antenna may be located inside the drill pipe in some embodiments. For transmission from the surface to downhole, the transmitting antenna may be placed around an outer diameter (OD) of the drill pipe in some embodiments. It will be appreciated that one or more transmitting antennas may be placed at any location in the downhole environment.

It should be noted that tightly-wound solenoid antennas may behave differently from helical antennas that are wound with a pitch corresponding to the transmitted wavelength. The latter is well-understood and utilized in many applications, while the former is not often utilized as it is not as well-understood.

Referring to FIG. 9 , a diagram 900 illustrates a top view and a perspective view of an example antenna design for a surface signal transceiver assembly, in accordance with some embodiments. FIG. 9 illustrates that the antenna design includes a transmit antenna 902, a receive antenna 904, and optionally a research antenna 906 (which may utilized for investigating the network without interfering with the other signals). In some embodiments, the antenna design depicted in FIG. 9 may be utilized in the first signal transceiver assembly 102 depicted in FIGS. 2A, 3A, and 4A. For example, the transmit antenna 902 of FIG. 9 may correspond to the transmit antenna 212 depicted in FIGS. 2A, 3A, and 4A, and the receive antenna 904 of FIG. 9 may correspond to the receive antenna 216 depicted in FIGS. 2A, 3A, and 4A.

The present disclosure contemplates two methods to receive a transmitted signal. The first method relies on electromagnetic (EM) coupling/mutual inductance between the transmitted evanescent electromagnetic field and the coil antenna. The first method utilizes a large diameter tightly-wound solenoid inside or outside of the periphery of any conductive part in the downhole environment. The second method relies on galvanic coupling of the transmitted signal. The second method utilizes welding/brazing/soldering/mechanical coupling of a wire to anything metal that is in the downhole environment. In a particular embodiment, the transmitted signal may be received by using the first method (i.e., EM coupling/mutual inductance of the transmitted evanescent field) and by using the second method (i.e., galvanic coupling) for the electric field of the surface wave.

For reception of signals sent from the downhole environment to the surface, the receiver antenna of the present disclosure may be placed about the drill pipe (during the drilling and completions stage), according to some embodiments. In some cases, it may be advantageous to place the receiver antenna inside the bell nipple or rotating housing or to place the receiver antenna around a large piece of casing. For reception of signals sent from the surface to the downhole environment, the receiver antenna of the present disclosure may be placed concentrically inside the drill pipe (during the drilling and completions stage), according to some embodiments. Alternatively, downhole reception may be achieved by placing the receiver antenna on the outside diameter (OD) of the drill pipe or any casing member, according to some embodiments.

Referring to FIG. 10 , a diagram 1000 illustrates a top view of an example receiver design for a signal transceiver assembly, in accordance with some embodiments. In some embodiments, the design depicted in FIG. 10 may be utilized for the receiver 214 of the first signal transceiver assembly 102 depicted in FIGS. 2A, 3A, and 4A. In some embodiments, the design depicted in FIG. 10 may be utilized for the receiver 244 of the second signal transceiver assembly 104 depicted in FIGS. 2B, 3B, and 4B.

The receiver performs one of the last steps in the signal's transmission. The receiver is responsible for receiving the transmitted signal with satisfactory insertion loss, filtering out unwanted signals, amplifying signals, blocking very large signals, and finally demodulating signals. FIG. 10 illustrates a particular embodiment of a receiver design that includes a printed circuit board having: an envelope detector/filter 1002; a radio frequency (RF) switch 1004; and a low noise amplifier 1006.

The raw received signal is essentially a burst of a sinusoidal disturbance, which is not a one or a zero but instead just a very strong noise signal. Accordingly, the diodes, resistor and capacitor in the envelope detector/filter 1002 may be configured to convert that noise signal into a digital zero or lack thereof into a digital one, according to some embodiments. The filter of the envelope detector/filter 1002 may be configured to mitigate any unwanted noise signals which may interfere with high-fidelity reception of the transmitted signal, according to some embodiments. It will be appreciated that numerous other filtering and demodulating methods may be available that may be utilized in alternative embodiments.

As the transmitting antenna is in close proximity to the receiving antenna (as depicted in the example antenna designs of FIGS. 8 and 9 ), the transmitting antenna may “jam” the neighboring receiving antenna by causing it to receive such a large signal that push transmitters into a state of saturation, from which they cannot recover quickly enough to receive a small signal. Accordingly, the RF switch 1004 may be configured to essentially mute the receiver when the neighboring transmitter is transmitting. Once transmission has completed, the receiver is unmuted and is then able to receive very small signals.

An array of NPN, PNP bipolar junction transistors may be arranged to form the low noise amplifier 1006. The low noise amplifier 1006 receives a small filtered signal and amplifies its voltage and/or current to levels that are satisfactory for interaction with a microprocessor.

As previously described herein, antennas operating at their resonant frequency, or any harmonic, produce increased gain. This also applies in the downhole environment, as it too has a resonant frequency. Accordingly, the transmitting antenna may be engineered to match the resonant/harmonic frequency in the downhole environment in order to enhance the signal's transmitted gain, thereby increasing transmitted and received power.

While little information may be known regarding resonant frequencies in the downhole environment, this is a well-known phenomenon encountered in induction heating, and most induction heaters are configured to automatically adjust to operate at the environment's resonant frequency.

While not illustrated in the previous figures, one of ordinary skill in the art will appreciate that signal boosters and repeaters may be utilized to improve the transmission distance and quality and/or to capture more data from along the path of power/telemetry transmission (among other possibilities), in some embodiments.

Referring to FIG. 11 , a flow diagram 1100 illustrates an example of a process of utilizing surface waves for communication in a downhole environment during a drilling and completion stage, according to some embodiments.

At operation 1110, the process includes utilizing a transmitter and a transmit antenna of a first signal transceiver assembly to transmit communication signal(s) to a second signal transceiver assembly in a downhole environment. The communication signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 2A, the first signal transceiver assembly 102 may be positioned on the OD of the drill pipe 124. The first signal transceiver assembly 102 may utilize the transmitter 210 and the transmit antenna 212 to transmit communication signal(s) to the second signal transceiver assembly 104 (as shown in FIG. 2B). The communication signal(s) are transmitted via surface waves that propagate along the interface between the air 112 (a dielectric) and the drill pipe 124 (a conductor).

At operation 1120, the process includes utilizing a receiver and a receive antenna of the second signal transceiver assembly to receive the communication signal(s) from the first signal transceiver assembly. For example, referring to FIG. 2B, the second signal transceiver assembly 104 may utilize the receiver 244 and the receive antenna 246 to receive the communication signal(s) from the first signal transceiver assembly 102 (as shown in FIG. 2A).

At operation 1130, the process includes utilizing a transmitter and a transmit antenna of the second signal transceiver assembly to transmit communication signal(s) to the first signal transceiver assembly. The communication signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 2B, the second signal transceiver assembly 104 may be positioned on the ID of the drill pipe 124 immersed in the drilling fluid 126. The second signal transceiver assembly 104 may utilize the transmitter 240 and the transmit antenna 242 to transmit communication signal(s) to the first signal transceiver assembly 102 (as shown in FIG. 2A). The communication signal(s) are transmitted via surface waves that propagate along the interface between the drilling fluid 126 (a dielectric) and the drill pipe 124 (a conductor).

Thus, FIG. 11 illustrates an example of a process of utilizing surface waves for communication in a downhole environment during a drilling and completion stage.

Referring to FIG. 12 , a flow diagram 1200 illustrates an example of a process of utilizing surface waves for power transmission in a downhole environment during a drilling and completion stage, according to some embodiments.

At operation 1210, the process includes utilizing a transmitter and a transmit antenna of a first signal transceiver assembly to transmit power signal(s) to a second signal transceiver assembly in a downhole environment. The power signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 2A, the first signal transceiver assembly 102 may be positioned on the OD of the drill pipe 124. The first signal transceiver assembly 102 may utilize the transmitter 210 and the transmit antenna 212 to transmit power signal(s) to the second signal transceiver assembly 104 (as shown in FIG. 2B). The power signal(s) are transmitted via surface waves that propagate along the interface between the air 112 (a dielectric) and the drill pipe 124 (a conductor).

At operation 1220, the process includes utilizing a receiver and a receive antenna of the second signal transceiver assembly to receive the power signal(s) from the first signal transceiver assembly. For example, referring to FIG. 2B, the second signal transceiver assembly 104 may be positioned on the ID of the drill pipe 124 immersed in the drilling fluid 126. The second signal transceiver assembly 104 may utilize the receiver 244 and the receive antenna 246 to receive the power signal(s) from the first signal transceiver assembly 102 (as shown in FIG. 2A). The power signal(s) are received as surface waves that propagate along the interface between the drilling fluid 126 (a dielectric) and the drill pipe 124 (a conductor).

At operation 1230, the process includes utilizing the received power signal(s) at the second signal transceiver assembly to provide power to tool(s) in the downhole environment. For example, referring to FIG. 2B, the second signal transceiver assembly 104 may utilize the received power signal(s) to provide power to tool(s) in the downhole environment, such as a measurement-while-drilling (MWD) tool (not shown), among other possibilities.

Thus, FIG. 12 illustrates an example of a process of utilizing surface waves for power transmission in a downhole environment during a drilling and completion stage.

Referring to FIG. 13 , a flow diagram 1300 illustrates an example of a process of utilizing surface waves for communication in a downhole environment during a production stage, according to some embodiments.

At operation 1310, the process includes utilizing a transmitter and a transmit antenna of a first signal transceiver assembly to transmit communication signal(s) to a second signal transceiver assembly in a downhole environment. The communication signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 3A, the first signal transceiver assembly 102 may be positioned on the OD of the production pipe 324. The first signal transceiver assembly 102 may utilize the transmitter 210 and the transmit antenna 212 to transmit communication signal(s) to the second signal transceiver assembly 104 (as shown in FIG. 2B). The communication signal(s) are transmitted via surface waves that propagate along the interface between the air 112 (a dielectric) and the production pipe 324 (a conductor).

At operation 1320, the process includes utilizing a receiver and a receive antenna of the second signal transceiver assembly to receive the communication signal(s) from the first signal transceiver assembly. For example, referring to FIG. 3B, the second signal transceiver assembly 104 may utilize the receiver 244 and the receive antenna 246 to receive the communication signal(s) from the first signal transceiver assembly 102 (as shown in FIG. 3A).

At operation 1330, the process includes utilizing a transmitter and a transmit antenna of the second signal transceiver assembly to transmit communication signal(s) to the first signal transceiver assembly. The communication signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 3B, the second signal transceiver assembly 104 may be positioned on the ID of the production pipe 324 immersed in the production fluid 326. The second signal transceiver assembly 104 may utilize the transmitter 240 and the transmit antenna 242 to transmit communication signal(s) to the first signal transceiver assembly 102 (as shown in FIG. 3A). The communication signal(s) are transmitted via surface waves that propagate along the interface between the production fluid 326 (a dielectric) and the production pipe 324 (a conductor).

Thus, FIG. 13 illustrates an example of a process of utilizing surface waves for communication in a downhole environment during a production stage.

Referring to FIG. 14 , a flow diagram 1400 illustrates an example of a process of utilizing surface waves for power transmission in a downhole environment during a production stage, according to some embodiments.

At operation 1410, the process includes utilizing a transmitter and a transmit antenna of a first signal transceiver assembly to transmit power signal(s) to a second signal transceiver assembly in a downhole environment. The power signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 3A, the first signal transceiver assembly 102 may be positioned on the OD of the production pipe 324. The first signal transceiver assembly 102 may utilize the transmitter 210 and the transmit antenna 212 to transmit power signal(s) to the second signal transceiver assembly 104 (as shown in FIG. 3B). The power signal(s) are transmitted via surface waves that propagate along the interface between the air 112 (a dielectric), or the production fluid 326 (also a dielectric) in some embodiments, and the production pipe 324 (a conductor).

At operation 1420, the process includes utilizing a receiver and a receive antenna of the second signal transceiver assembly to receive the power signal(s) from the first signal transceiver assembly. For example, referring to FIG. 3B, the second signal transceiver assembly 104 may be positioned on the ID of the production pipe 324 immersed in the production fluid 326. The second signal transceiver assembly 104 may utilize the receiver 244 and the receive antenna 246 to receive the power signal(s) from the first signal transceiver assembly 102 (as shown in FIG. 3A). The power signal(s) are received as surface waves that propagate along the interface between the production fluid 326 (a dielectric) and the production pipe 324 (a conductor).

At operation 1430, the process includes utilizing the received power signal(s) at the second signal transceiver assembly to provide power to tool(s) in the downhole environment. For example, referring to FIG. 3B, the second signal transceiver assembly 104 may utilize the received power signal(s) to provide power to tool(s) in the downhole environment, such as a production tool (not shown), among other possibilities.

Thus, FIG. 14 illustrates an example of a process of utilizing surface waves for power transmission in a downhole environment during a production stage.

Referring to FIG. 15 , a flow diagram 1500 illustrates an example of a process of utilizing surface waves for communication in a downhole environment during an abandonment stage, according to some embodiments.

At operation 1510, the process includes utilizing a transmitter and a transmit antenna of a first signal transceiver assembly to transmit communication signal(s) to a second signal transceiver assembly in a downhole environment. The communication signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 4A, the first signal transceiver assembly 102 may be positioned between an ID of the fifth casing layer 120(e) and the barrier material 422 that replaces the production fluid 326 and the production pipe 324 during the abandonment stage. The first signal transceiver assembly 102 may utilize the transmitter 210 and the transmit antenna 212 to transmit communication signal(s) to the second signal transceiver assembly 104 (as shown in FIG. 4B). The communication signal(s) are transmitted via surface waves that propagate along the interface between the barrier material 422 (a dielectric) and the fifth casing layer 120(e) (a conductor).

At operation 1520, the process includes utilizing a receiver and a receive antenna of the second signal transceiver assembly to receive the communication signal(s) from the first signal transceiver assembly. For example, referring to FIG. 4B, the second signal transceiver assembly 104 may utilize the receiver 244 and the receive antenna 246 to receive the communication signal(s) from the first signal transceiver assembly 102 (as shown in FIG. 4A).

At operation 1530, the process includes utilizing a transmitter and a transmit antenna of the second signal transceiver assembly to transmit communication signal(s) to the first signal transceiver assembly. The communication signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 4B, the second signal transceiver assembly 104 may be positioned between the ID of the fifth casing layer 120(e) and the barrier material 422. The second signal transceiver assembly 104 may utilize the transmitter 240 and the transmit antenna 242 to transmit communication signal(s) to the first signal transceiver assembly 102 (as shown in FIG. 4A). The communication signal(s) are transmitted via surface waves that propagate along the interface between the barrier material 422 (a dielectric) and the fifth casing layer 120(e) (a conductor).

Thus, FIG. 15 illustrates an example of a process of utilizing surface waves for communication in a downhole environment during an abandonment stage.

Referring to FIG. 16 , a flow diagram 1600 illustrates an example of a process of utilizing surface waves for power transmission in a downhole environment during an abandonment stage, according to some embodiments.

At operation 1610, the process includes utilizing a transmitter and a transmit antenna of a first signal transceiver assembly to transmit power signal(s) to a second signal transceiver assembly in a downhole environment. The power signal(s) are transmitted via surface waves that propagate along a dielectric/conductor interface. For example, referring to FIG. 4A, the first signal transceiver assembly 102 may be positioned between an ID of the fifth casing layer 120(e) and the barrier material 422 that replaces the production fluid 326 and the production pipe 324 during the abandonment stage. The first signal transceiver assembly 102 may utilize the transmitter 210 and the transmit antenna 212 to transmit power signal(s) to the second signal transceiver assembly 104 (as shown in FIG. 4B). The power signal(s) are transmitted via surface waves that propagate along the interface between the barrier material 422 (a dielectric) and the fifth casing layer 120(e) (a conductor).

At operation 1620, the process includes utilizing a receiver and a receive antenna of the second signal transceiver assembly to receive the power signal(s) from the first signal transceiver assembly. For example, referring to FIG. 4B, the first signal transceiver assembly 102 may be positioned between an ID of the fifth casing layer 120(e) and the barrier material 422. The second signal transceiver assembly 104 may utilize the receiver 244 and the receive antenna 246 to receive the power signal(s) from the first signal transceiver assembly 102 (as shown in FIG. 4A). The power signal(s) are received as surface waves that propagate along the interface between the barrier material 422 (a dielectric) and the fifth casing layer 120(e) (a conductor).

At operation 1630, the process includes utilizing the received power signal(s) at the second signal transceiver assembly. For example, referring to FIG. 4B, the second signal transceiver assembly 104 may utilize the received power signal(s) to provide power in the downhole environment during the abandonment stage.

Thus, FIG. 16 illustrates an example of a process of utilizing surface waves for power transmission in a downhole environment during an abandonment stage.

FIG. 17 is a block diagram illustrating an example computer system 1700 that is used to implement one or more portions of a system that utilizes surface waves for signal transmission in a downhole environment, according to some embodiments. For example, the computer system 1700 may be a computing device that is communicatively coupled to one or more devices that implement one or more operations related to the subject matter of the present disclosure. As an illustrative, non-limiting example, the computer system 1700 may be utilized to capture and/or display information received from the first signal transceiver assembly 102 as shown in FIG. 1 .

Computer system 1700 may be implemented using a variety of computing devices, such as a personal computer system, desktop computer, laptop or notebook computer, mainframe computer system, handheld computer, workstation, network computer, a consumer device, application server, mobile telephone, or some other type of computing device.

As shown, computer system 1700 includes one or more processors 1710, which may include multiple cores coupled to a system memory 1720 via an input/output (I/O) interface 1730. Computer system 1700 further includes a network interface 1740 coupled to I/O interface 1730. In some embodiments, computer system 1700 may be a uniprocessor system including one processor 1710, or a multiprocessor system including several processors 1710 a-n, as shown. The processors 1710 may be any suitable processors capable of executing instructions. For example, in various embodiments, processors 1710 may implement one of a number of instruction set architectures (ISAs), such as the x86, PowerPC, SPARC, or MIPS ISA.

As shown, the computer system 1700 may also include one or more network communication devices (e.g., network interface 1740) for communicating with other systems and/or components over a communications network. For example, an instance of an application executing on computer system 1700 may use network interface 1740 to communicate with another server application executing on another computer system, as described herein.

As shown, computer system 1700 may use its network interface 1740 to communicate with one or more other devices 1760, such as persistent storage devices and/or one or more I/O devices. In some embodiments, some of these other devices may be implemented locally on the computer system 1700, accessible via the I/O interface 1730. In various embodiments, persistent storage devices may include disk drives, tape drives, solid state memory, other mass storage devices, or any other persistent storage device. The computer system 1700 may store instructions and/or data in persistent storage devices, and retrieve the stored instruction and/or data as needed.

As shown, the computer system 1700 may include one or more system memories 1720 that store instructions and data accessible by processor(s) 1710. In various embodiments, system memories 1720 may be implemented using any suitable memory technology, (e.g., one or more of cache, static random-access memory (SRAM), DRAM, RDRAM, EDO RAM, DDR 10 RAM, synchronous dynamic RAM (SDRAM), EEPROM, non-volatile/Flash-type memory, etc.). The system memory 1720 may be used to store code 1725 or executable instructions to implement the methods and techniques described herein. For example, the executable instructions may include instructions to implement the <>, as discussed. The system memory 1720 may also be used to store data 1726 needed or produced by the executable instructions.

In some embodiments, some of the code 1725 or executable instructions may be persistently stored on the computer system 1700 and may have been loaded from external storage media. The persistent storage of the computer system 1700 and the external media are examples of non-transitory computer-readable storage media, which may be used to store program instructions to be executed by the computer system 1700. A non-transitory computer-readable storage medium may provide the capability to store information in a form readable by a machine (e.g., computer system 1700). Non-transitory computer-readable media may include storage media such as magnetic or optical media, disk or DVD/CD-ROM devices, archival tapes, network-attached storage systems, or other computer systems.

In some embodiments, the I/O interface 1730 may be configured to coordinate I/O traffic between processor 1710, system memory 1720 and any peripheral devices in the system, including through network interface 1740 or other peripheral interfaces. In some embodiments, I/O interface 1730 may perform any necessary protocol, timing or other data transformations to convert data signals from one component (e.g., system memory 1720) into a format suitable for use by another component (e.g., processor 1710). In some embodiments, I/O interface 1730 may include support for devices attached through various types of peripheral buses, such as a variant of the Peripheral Component Interconnect (PCI) bus standard or the Universal Serial Bus (USB) standard, for example. In some embodiments, the function of I/O interface 1730 may be split into two or more separate components, such as a north bridge and a south bridge, for example. Also, in some embodiments, some or all of the functionality of I/O interface 1730, such as an interface to system memory 1720, may be incorporated directly into processor 1710.

In some embodiments, the network interface 1740 may allow data to be exchanged between computer system 1700 and other devices attached to a network. The network interface 1740 may also allow communication between computer system 1700 and various I/O devices and/or remote storage systems. Input/output devices may, in some embodiments, include one or more display terminals, keyboards, keypads, touchpads, scanning devices, voice or optical recognition devices, or any other devices suitable for entering or retrieving data by one or more computer systems. Multiple input/output devices may be present in computer system 1700 or may be distributed on various nodes of a distributed system that includes computer system 1700. In some embodiments, similar input/output devices may be separate from computer system 1700 and may interact with one or more nodes of a distributed system that includes computer system 1700 through a wired or wireless connection, such as over network interface 1740. Network interface 1740 may commonly support one or more wireless networking protocols (e.g., Wi-Fi/IEEE 802.11, or another wireless networking standard). In some embodiments, the network interface 1740 may support communication via telecommunications/telephony networks such as analog voice networks or digital fiber communications networks, via storage area networks such as Fibre Channel SANs, or via any other suitable type of network and/or protocol.

Various modifications and changes may be made as would be obvious to a person skilled in the art having the benefit of this disclosure. The various embodiments described herein are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. These and other variations, modifications, additions, and improvements may fall within the scope of embodiments as defined in the claims that follow. 

What is claimed is:
 1. A system, comprising: a first signal transceiver assembly located in a surface environment of a well; and a second signal transceiver assembly located in a downhole environment of the well; wherein the first signal transceiver assembly is configured to transmit a set of communication signals to the second signal transceiver assembly via surface waves that propagate from the surface environment to the downhole environment along an interface between one or more dielectric fluids and a conductive layer; and wherein the second signal transceiver assembly is configured to receive the set of communication signals from the first signal transceiver assembly via the surface waves that propagate along the interface.
 2. The system of claim 1, wherein the one or more dielectric fluids include air, and wherein the conductive layer is a drill pipe.
 3. The system of claim 2, wherein the first signal transceiver assembly is positioned along an outer diameter (OD) of the drill pipe.
 4. The system of claim 1, wherein the one or more dielectric fluids include a drilling fluid, and wherein the conductive layer is a drill pipe.
 5. The system of claim 4, wherein the second signal transceiver assembly is positioned along an inner diameter (ID) of the drill pipe.
 6. The system of claim 1, wherein the one or more dielectric fluids include air, and wherein the conductive layer is a production pipe.
 7. The system of claim 6, wherein the first signal transceiver assembly is positioned along an outer diameter (OD) of the production pipe.
 8. The system of claim 1, wherein the one or more dielectric fluids include a production fluid, and wherein the conductive layer is a production pipe.
 9. The system of claim 8, wherein the second signal transceiver assembly is positioned along an inner diameter (ID) of the production pipe.
 10. The system of claim 1, wherein: the first signal transceiver assembly comprises a transmitter and a transmit antenna configured to transmit the set of communication signals to the second signal transceiver assembly; the transmitter includes a printed circuit board comprising a 555 timer, a gate driver, and a Darlington Amplifier Array; and the transmit antenna includes a solenoid antenna.
 11. A signal transceiver assembly located in a surface environment of a well, the signal transceiver assembly comprising: a transmitter and a transmit antenna configured to transmit a first set of communication signals to a downhole signal transceiver assembly located in a downhole environment of the well via a first set of surface waves that propagate from the surface environment to the downhole environment along an interface between one or more dielectric fluids and a conductive layer; and a receiver and a receive antenna configured to receive a second set of communication signals from the downhole signal transceiver assembly via a second set of surface waves that propagate from the downhole environment to the surface environment along the interface between the one or more dielectric fluids and the conductive layer.
 12. The signal transceiver assembly of claim 11, wherein: the transmitter includes a printed circuit board comprising a 555 timer, a gate driver, and a Darlington Amplifier Array; and the transmit antenna includes a solenoid antenna.
 13. The signal transceiver assembly of claim 11, wherein: the receiver includes a printed circuit board comprising an envelope detector and filter, a radio frequency (RF) switch, and a low noise amplifier; and the receive antenna includes a solenoid antenna.
 14. The signal transceiver assembly of claim 11, wherein the one or more dielectric fluids include at least one of air or a drilling fluid, wherein the conductive layer is a drill pipe, and wherein the signal transceiver assembly is positioned along an outer diameter (OD) of the drill pipe.
 15. The signal transceiver assembly of claim 11, wherein the one or more dielectric fluids include at least one of air or a production fluid, wherein the conductive layer is a production pipe, and wherein the signal transceiver assembly is positioned along an outer diameter (OD) of the production pipe.
 16. A signal transceiver assembly located in a downhole environment of a well, the signal transceiver assembly comprising: a receiver and a receive antenna configured to receive a first set of communication signals from a surface signal transceiver assembly located in a surface environment of the well via a first set of surface waves that propagate from the surface environment to the downhole environment along an interface between one or more dielectric fluids and a conductive layer; and a transmitter and a transmit antenna configured to transmit a second set of communication signals to the surface signal transceiver assembly via a second set of surface waves that propagate from the downhole environment to the surface environment along the interface between the one or more dielectric fluids and the conductive layer.
 17. The signal transceiver assembly of claim 16, wherein: the transmitter includes a printed circuit board comprising a 555 timer, a gate driver, and a Darlington Amplifier Array; and the transmit antenna includes a solenoid antenna.
 18. The signal transceiver assembly of claim 16, wherein: the receiver includes a printed circuit board comprising an envelope detector and filter, a radio frequency (RF) switch, and a low noise amplifier; and the receive antenna includes a solenoid antenna.
 19. The signal transceiver assembly of claim 16, wherein the one or more dielectric fluids include a drilling fluid, wherein the conductive layer is a drill pipe, and wherein the signal transceiver assembly is positioned along an inner diameter (ID) of the drill pipe.
 20. The signal transceiver assembly of claim 16, wherein the one or more dielectric fluids include a production fluid, wherein the conductive layer is a production pipe, and wherein the signal transceiver assembly is positioned along an inner diameter (ID) of the production pipe. 